An Israeli firm has developed a 77 pound helicopter UAV for military (and civilian) use. The Black Eagle 50 carries a 6.6 pound sensor payload, has a top speed of 70 kilometers an hour, an endurance of three hours and can operate up to ten kilometers from the operator.
There have been several of these helicopter UAVs developed over the last decade, but few have found an enthusiastic reception from the military. For example, the U.S. Army has had a hard time finding enthusiastic users for its RQ-16A UAV. Although it successfully tested this miniature helicopter UAV, originally called the MAV (Micro Air Vehicle), in Iraq, only the U.S. Navy ordered some (372). The 20 pound (8.4 kg) vehicle can fly as high as 10,500 feet, and carries day and night cameras. The MAV is most useful in urban environments, where it can quickly flit around buildings and other obstacles. What attracted the navy order, and some interest in Britain, was the RQ-16As ability to assist EOD (Explosive Ordnance Disposal) troops who search for, and clear, roadside bombs in Iraq and Afghanistan. The RQ-16A (equipped with one downward looking vidcam, and one looking forward) can quickly go to suspicious objects, hover nearby and allow the UAV operator to get a detailed look. This is often all it takes. If not, a ground robot, with a robotic hand, can be rolled up, to pick at the suspicious object.
The MAV has its blades contained within a cylindrical enclosure, and uses software control to keep it stable in flight. All the operator has to do is tell it where to go. Endurance, as with helicopters, depends on altitude. At sea level, the MAV will stay in the air for about 40 minutes, before it has to be refueled (it uses the same fuel as military vehicles.) The UAV can operate up to 11 kilometers from the ground station, and has a top speed of about 1.5 kilometers a minute. It cannot operate if there is a wind of more than 28 kilometers (17 MPH) an hour.
When operating at 10,000 feet (typical in Afghanistan) it can stay in the air for only about 20 minutes. The MAV and control equipment can be carried in a special container which, when loaded weighs about 40 pounds. It can be backpacked. The MAV costs about $35,000. A complete RQ-16A system consists of two UAVs and a ground station.
The MAV was designed in a more compact package, instead of just producing a miniature helicopter (like the Black Eagle 50). But even the more compact form factor did not overcome the resistance to helicopter UAVs.
The problem with helicopter UAVs is that the ability hover, while useful, is not as important as being able to stay over an area for hours and hours, passing on video of what is going on down there. Fixed wing UAVs can do that more cheaply and reliably than can helicopter UAVs.